Egg Mass Index Research Articles

Environmentally safe substances for controlling the root-knot nematode, Meloidogyne arenaria infested potato and their influence on yield and alkaloidal content in Egypt

The nematicidal action of three seed mill wastes from cress (Eruca sativa Mill.), castor (Ricinus communis L.) and linseed (Linum usitatissimum L.) as soil additives were tested at three rates (on base lower rate, recommended rate and higher rate), under field conditions at the research and production station of the National Research Centre, El-Nubaria district, El-Beheira governorate, Western Nile Delta region, Egypt, to study the physiological influence of these substances on potato yield, their role against Meloidogyne arenaria infection and the alkaloidal content. All the evaluated treatments significantly (p ⩽ 0.05 and/or 0.01) reduced the numbers of juveniles in soil and in roots, number of galls, egg masses, gall and egg mass indices and consequently rate of nematode build-up as compared to untreated plants(control). Statistical differences in the nematode stages were found within and between treatments. The percentage of reduction in the nematode stages was comparatively more with using of Linseed mill wastes followed by castor seed mill wastes, then cress seed mill wastes. Regarding to the potato yield, all the evaluated amendments achieved significantly (p ⩽ 0.05 and/or 0.01) increased, total contents of alkaloidal content as compared to untreated plants. On the other hand, all the evaluated amendments achieved significantly (p ⩽ 0.05 and/or 0.01) decreased the solanine values as compared to untreated plants. These results indicate that some natural compounds may be used as natural nematicides in controlling M. arenaria nematode and improving the quality and yield of potato plants.

Histological Interactions of Paecilomyces lilacinus with Root-knot Nematode Meloidogyne incognita and Their Effect on the Growth of Tomato

A glasshouse experiment was conducted to assess the effect of Paecilomyces lilacinus on the reproduction of root-knot nematode and on the growth of tomato. Data on the plant growth, leaf area, yield characteristics, root-knot and egg-mass indices were recorded. The histological interactions studies were also carried out to check the parasitism of root-knot nematode eggs by P. lilacinus. The results indicated that the use of P. lilacinus one week before nematode inoculation caused an increase in growth and yield characteristics of tomato, and also reduced the reproduction of nematode as compared to other treatments. The results of histological studies indicated that P. lilacinus parasitized on the M. incognita eggs through the formation of fungal hyphae and conidiophores and caused the disintegration of the eggshells, egg masses and juveniles of M. incognita.

Genotypic Diversity of Potato Germplasm against Root Knot Nematode (Meloidogyne incognita) Infection in Pakistan

Potato (Solanum tuberosum), an important vegetable crop of Pakistan endures significant yield losses due to root knot nematode (Meloidogyne incognita).. Research wok was designed to identify resistant potato germplasm against RKN (Meloidogyne incognita) infection. A field trial was conducted in the research area of Department of Plant Pathology, University of Agriculture Faisalabad. Thirty six (36) potato verities/ cultivars relocated five times were sown in four years sick plot containing root knot nematode (Meloidogyne incognita) in RCBD layout. Root knot nematode reproduction and host damage was accessed by recording nematode root galls and egg mass indices, root weight, shoot weight, , number of leaves, fruit weight, rate of reproduction and final population of nematodes. Experiment revealed a considerable variation in response against Meloidogyne incognita infection among the genotype tested but none of the single cultivar was immune. FD-8-1 was used as negative control. The cultivar FD-19-2 was highly susceptible followed by SH-692 and SH-5. All other cultivars had less galling index with low fecundity rate indicating their ability to suppress the adult female reproduction. The cultivar FD-1-3 scored least number of galls and egg mass indices followed by FD-49-62, SH-339 and SH-332.

New sources of resistance to Meloidogyne incognita race 3 in wild cotton accessions and histological characterization of the defence mechanisms

Accessions of Gossypium spp., some of them never previously tested, were evaluated for resistance to a local isolate of Meloidogyne incognita race 3 in greenhouse experiments. Nematode infection was characterized based on the galling and egg mass indexes and the reproduction factors (RF). Root‐knot nematode reproduction among the newly tested accessions varied from highly susceptible (AS0188, AS0189) to moderately resistant (MT123 no. 3), and some accessions showed highly reduced nematode reproduction (CIR1343, CIR1348, Fai Mui). Histological observations of two resistant accessions (G. barbadense CIR1348 and G. hirsutum TX‐25, respectively) showed that resistance occurs through a two‐stage mechanism in the first accession and through a single‐stage mechanism in the second. Parasitism is blocked early after second‐stage juvenile (J2) penetration or during its initial tissue migration (CIR1348) and the development of later‐stage juveniles into female adults is suppressed at a later stage (TX‐25 and CIR1348). Fluorescence and bright light microscopy showed that root cells surrounding nematodes exhibit a hypersensitivity‐like reaction, with the accumulation of presumably phenolic compounds and the presence of necrotic cells that limit the development of nematodes and the formation of giant cells. Underdeveloped giant cells with degenerated cytoplasmic content were found in small numbers in CIR1348 and in large numbers in TX‐25, along with deformed nematodes. The full characterization of the defence mechanisms of novel sources of resistance to the root‐knot nematode in cotton constitutes a first step towards their use in crop improvement.

Role of organic soil amendments with some non-conventional plant additives on the growth of eggplant and their role against Meloidogyne incognita infection

The effects of four waste residues from castor (Ricinus communis L.), rocket (Eruca sativa Mill.), linseed (Linum usitatissimum L.) and wheat germ (Triticum aestivum L.) crops oil extraction as soil amendments at three rates (on base lower rate, recommended rate and higher rate), in comparison with the nematicide Nemacur 10% G were evaluated in greenhouse conditions (25 ± 5°C) at the National Research Center, Egypt, during two successive seasons on the physiological influence on the eggplant and on the infection by the root-knot nematode Meloidogyne incognita. All the tested treatments significantly reduced the numbers of juveniles in soil or in roots, number of galls, egg-masses, gall and egg-mass indices and the rate of nematode build-up. Significant differences in the nematode stages were found within and between treatments. The percentage reduction in the nematode stages was greater with the use of wheat germ mill residues (WGMR) compound followed by castor seed mill residues (CAMR) compound, rocket seed mill residues (RSMR) and Nemacur 10% G. The application of linseed mill residues (LSMR) was the least effective in reducing the nematode stages. Regarding infected plants, all the evaluated amendments achieved significant increases in the almost shoot and root growth variables, total contents of photosynthetic pigments, phenolics and carbohydrates when compared with nematode inoculated and untreated plants. As for healthy plants, it is clear that all the doses of WGMR compound and the highest doses (3.75%, w/w) of the other additives had pronounced effect on the growth parameters and phenolic content of dry leaves of the eggplant. In addition, all the treatments increased photosynthetic pigments and carbohydrates content of the eggplant. These results indicate that some seed mill residues may be used as natural nematicides in controlling M. incognita nematode and improving the growth and some chemical composition of the eggplant.

Infectivity and reproduction of Meloidogyne incognita (Kofoid and White) Chitwood on African yam bean, Sphenostylis stenocarpa (Hochst Ex. A. Rich) Harms accessions as influenced by botanical soil amendments

A screen house experiment was conducted to study the effects of amendment of soil with leaf powders of some plants at different levels (5, 10, 15, 20 and 25 t/ha) on the infectivity and reproduction of Meloidogyne incognita (Kofoid and White) Chitwood on African yam bean, Sphenostylis stenocarpa (Hochst Ex . A. Rich) Harms. The plants were neem, drumstick, lemon grass, African peach and rattle weed. Results showed that botanical soil amendments significantly (P ≤ 0.05) improved growth of plants and reduced reproduction of M. incognita on African yam bean in varying degrees. The effects of botanicals on growth of plants and nematode reproduction increased with increase in concentrations/ amendment levels, and were highest at 25 t/ha. Cymbopogon citratus produced the highest manurial properties as it supported greater vegetative growth of plants while Moringa oleifera was most effective in the reduction of reproduction and development of M. incognita in the roots. M. oleifera produced the least gall index and egg mass index of 1.0, though Crotolaria retusa also recorded egg mass index of 1.0. Results from this study are indicative of the fact that local farmers could apply these botanicals as fertilizers during cultivation to counteract the effect of root-knot nematode, and also to improve growth of crop plants but field trials are necessary before final recommendation. Keywords: Infectivity, reproduction, African yam bean, Meloidogyne incognita , amendment

Distribution, frequency of occurrence and population density of root knot nematode in Hamelmalo – Eritrea

A survey was conducted during January to May 2011, to assess the occurrence and population density of root-knot nematode on different crops in 13 different localities of Hamelmalo subzone (Eritrea). A total 449 samples were collected from the study area and nematodes in their rhizosphere soil and root extracted by Cobb’s decanting and sieving technique, Baermann funnel technique and root maceration methods. Out of the 449 collected samples, 344 samples were found to be infested with root knot nematode as soil population was visible. Awatle (97.8%), Shewwa (90%) and Engdaw (88.2%) are the provinces of the Hamelmalo that had very high population of root knot nematode. The least infection was reported from the Stur (52.3%) province. At individual crop level, the highest frequency of occurrence was reported from tomato (86.5%) and least was from rocket (50%) crop. Root knot nematode population in 100 cc soil (density) was reported as maximum (73.5%) for the chilli crop and minimum (12.24%) for the rocket vegetable. Measurement of disease incidence was based on the gall index and egg mass index, and this varied from 2 to 5 on 5 point scale. Highest disease incidence (5 GI and EMI) was reported from tomato, okra and potato crops, followed by the spinach, chilli and molukhyia crop, while the least disease incidence (2 GI and EMI) was reported from the rocket crop. Key words: Root knot nematode, vegetable crops, frequency, density, disease incidence, Hamelmalo.

WILD SOLANACEAE: POTENTIAL FOR THE USE AS ROOTSTOCKS RESISTANT TO ROOT-KNOT NEMATODE (MELOIDOGYNE SPP.)

Wild plants belonging to the Solanaceae have been studied by Embrapa Vegetables for their resistance to soil-borne diseases such as bacterial wilt (Ralstonia solanacearum), Phytophthora blight (Phytophthora capsici), Fusarium wilt (Fusarium spp.), and nematodes. The resistance reactions of five wild Solanaceae: Solanum asperolanatum, Solanum stramonifolium, Solanum sp., Solanum paniculatum, and S. subinerme to two species of root-knot nematode, Meloidogyne incognita race 1 and M. mayaguensis were evaluated. ‘Rutgers’ (susceptible) and ‘Nemadoro’ (resistant) tomato were used as standard cultivars. The experiment was conducted in a completely randomized design and the treatments arranged in a factorial design 5×2 (five species of wild Solanaceae and two species of root-knot nematode), with six replications. The seedlings of the wild Solanaceae were maintained in pots, under greenhouse conditions and inoculated with 6000 eggs and juveniles of the root-knot nematode species/plant. Sixty days after inoculation the plants were evaluated for the egg mass index (EMI), gall index (GI), number of eggs/g of root (NEGR), and reproduction factor (RF). S. asperolanatum, S. stramonifolium, Solanum sp. were resistant to M. incognita race 1, while S. stramonifolium, Solanum paniculatum, and S. subinerme were resistant to M. mayaguensis.

REACTION OF WILD SOLANACEAE TO MELOIDOGYNE INCOGNITA RACE 1 AND M. JAVANICA

Under greenhouse conditions and in commercial fields, the advantages of grafting in the control of soil borne pathogens are evident. However, there is still need for further studies on the behaviour of species with potential for use as rootstocks concerning compatibility, productivity, and reaction to soil borne pathogens, especially nematodes. The reaction of five wild Solanaceae: Solanum asperolanatum, Solanum stramonifolium, Solanum sp., Solanum paniculatum, and S. subinerme to two species of root-knot nematode, Meloidogyne incognita race 1 and M. javanica was evaluated. ‘Rutgers’ (susceptible) and ‘Nemadoro’ (resistant) were used as standard cultivars. The experiment was conducted in a completely randomized design and the treatments arranged in a factorial 5×2 (five species of wild Solanaceae and two species of rootknot nematode), with six replications. The seedlings of the wild Solanaceae were maintained in pots, under greenhouse conditions and inoculated with 6000 eggs and juveniles of the root-knot nematode species/plant. 63 days after inoculation the plants were evaluated for the egg mass index (EMI), gall index (GI), number of eggs per gram of root (NEGR), and reproduction factor (RF). The species S. stramonifolium, S. paniculatum and S. subinerme were as resistant to M. javanica and a mixed population (M. incognita race 1 and M. javanica).

Host range study of Argentine Nacobbus aberrans sensu Sher populations and comments on the differential host test

The existence of races within the species Nacobbus aberrans sensu Sher has been confirmed; however, there is no consensus on a consistent system for race determination. Four plant species previously used as differential hosts in some N. aberrans race tests (tomato, pepper, sugarbeet and potato) were tested for susceptibility to seven nematode populations from Argentina. Plants were inoculated with second-stage juveniles and kept under glasshouse conditions at 21 °C for 90 days. The parameters evaluated (root gall index, egg mass index, and reproduction factor) in different nematode populations and plants showed significant differences. The reproductive fitness of the nematode populations differed among the plants that showed some degree of susceptibility. The results showed that N. aberrans comprises populations differing in host preference. Based on the nematode populations’ behaviour on these hosts, two groups were distinguished: i) populations that multiplied on all hosts, ii) populations that did not multiply on potato. The present work contributes to the analysis of criteria for developing a differential host test.

Soil application of Pseudomonas fluorescens and Trichoderma harzianum reduces root-knot nematode, Meloidogyne incognita, on tobacco

The effects of Pseudomonas fluorescens and Trichoderma harzianum , on the control of the rootknot nematode, Meloidogyne incognita , were investigated in three tobacco cultivars (RK-18 P8, RK-26 P3 and RK-12 P3). Soil application of the biocontrol agents was compared with two nematicides, Phorate and Furadan. Greatest reduction in the numbers of second-stage juveniles in soil, host root galls and egg mass indices were recorded with Furadan and P. fluorescens compared with experimental controls. The greatest increase in the plant growth and biomass of tobacco was obtained in cv. RK-18 P8 with P. fluorescens (16-32%) followed by Furadan (15-30 %) compared with experimental controls. Increases in total phenol (TP) and salicylic acid (SA) were negatively correlated with numbers of root galls and egg masses/root system. Greatest increases in the leaf contents of SA (20%) and TP (31%) were recorded in cv. RK-12 P3, whereas least increases were detected in cv. RK-18 P8 (17% TP and 10% SA). The study has revealed that cv. RK-12 P3 may be exploited commercially for nematode resistance to M. incognita , and P. fluorescens may be used as an alternative to nematicides in nematode infested field, to obtain higher productivity of tobacco.

Pseudomonas fluorescens for the Management of Root-knot Nematode Meloidogyne incognita in Tomato

A field experiment was conducted in Coimbatore district to study the efficacy of the biocontrol agent Pseudomonas fluorescens for the management of root-knot nematode Meloidogyne incognita in tomato. Soil application of the native isolates Pft 20 @ 2.5 kg/ha significantly reduced the nematode infestation in all the bacterized plants both in soil and roots with the least number of adult females, number of egg masses, number of eggs per egg mass and gall index and besides increased the plant growth, total soluble sugars and lycopene content of the fruit.

Weed Hosts of Root-Knot Nematodes and Their Distribution in Fiji

Weeds can act as reservoir hosts of a range of pests and diseases. Information and knowledge on the host status of weeds to common pests and diseases can be used to develop integrated weed and pest management strategies. As part of a survey on the distribution and diversity of root-knot nematodes on crops in Fiji, the root-knot nematode host status of weeds was also studied. Weeds growing in root-knot nematode infested farms (n= 189) and bioassay pot soil samples (n= 277) were identified, and their host status was determined on the basis of a root gall and egg-mass index scale from 0 to 5. A total of 45 weed species were recorded as potential weed hosts of root-knot nematodes with a gall index from 1 to 5. Using the weed and tomato bioassay method, a total of 11 nonhost weed species were recorded with a gall index of 0, relative to infected tomato growing in pot soil samples. Common weeds infected by root-knot nematodes on farms and in bioassay pot soil included slender amaranth, old world diamond-flower, tropic ageratum, sicklepod, mimbra, balsamapple, purple bushbean, little ironweed, ivy gourd, and cutleaf groundcherry. The presence of egg masses on the weed hosts indicated their ability to sustain root-knot nematode populations and, thus, their potential to act as reservoir hosts.

Effect of various levels of dietary Jatropha curcas seed meal on rabbits infested by the adult ticks of Hyalomma marginatum marginatum I. Animal performance, anti-tick feeding and haemogram

The goal of this study was to investigate the use of Jatropha curcas seed meal (JCSM) in different levels as acaricide in diet of rabbits experimentally infested by Hyalomma marginatum marginatum then determining animal performance, anti-tick feeding and its effects on haemogram of rabbits. Thirty healthy mixed-breed rabbits were randomly divided into five equal groups. The first group was kept as a control fed soya bean meal (20%) as a source of protein. Groups from the second to the fifth fed diets contained 2.5%, 5%, 7.5% and 10% of JCSM instead of soya bean meal as a source of protein, respectively. Feeding and watering were given freely throughout the study. Animal performance for treatment groups were recorded from the 1st week up to the 6th week. Then each group divided into two subgroups, and the ticks were introduced to all of one subgroup and the other kept as control, following them until dropped at the end of the 8th week for all groups of the experiment. Feeding and reproductive performance of the adult tick females were determined. Blood samples were collected and analysed for haematological examination at the 0, 6th and 8th weeks post-treatment from all animals. Result revealed that rabbits received diets containing 5%, 7.5% and 10% had significantly (P < 0.05) lower growth performance than control and 2.5% JCSM groups. Feed intake and body weight gain decreased with increasing the level of JCSM in the diet. The result of anti-tick feeding observed that the highest percentage (60-90%) of rejection was recorded in 10% of JCSM group then the other treated groups (20-30%). Egg mass and reproductive index per female were marked increase (P < 0.001) in groups 2.5%, 5% and 7.5% of JCSM. Macrocytic normochromic anaemia was development after 8 weeks of treatment, which changed to microcytic normochromic anaemia after challenge of ticks in groups received 5%, 7.5% and 10% JCSM. Leukopenia, neutopenia and lymphopenia were noticed (P < 0.05) in all treated groups which more drop in the group received 7.5% JCSM. Also, monocytosis was recorded in 7.5% and 10% JCSM groups. In conclusion, JCSM could be use in the treatment of ectoparasites at level less than 10% in diet. Further investigations should be done to detoxification the Jatropha seed meal to decrease the level of its toxicity.

Reaction of coffee cultivars Tupi IAC 1669-33 and IPR 100 to nematode Meloidogyne paranaensis

The aim of this research was to evaluate the resistance of the cultivars Tupi IAC 1669-33 and IPR 100 exposed to different inoculum levels of M. paranaensis. The parameters gall and egg mass index, reproduction factor (RF), susceptibility host index and reduction in the reproduction factor were used to classify the resistance reactions of the cultivars Tupi IAC 1669-33 (selection IAPAR 88480-8), IPR 100 and Catuai Vermelho IAC 81 (susceptible standard). The evaluations were carried out 80 days after inoculation in plants with six pairs of leaves planted in recipients with 120 mL. The inoculum levels used were 500, 1000, 1500 and 2000 eggs per plant. 'Tupi IAC 1669-33' and 'IPR 100' presented moderate resistance with the inoculum levels 500 and 1000 eggs. At the inoculum levels 1500 and 2000 eggs these two cultivars were classified as susceptible, but with lesser RF than the susceptible standard.

Reaction of coffee genotypes to different populations of Meloidogyne spp.: detection of a naturally virulent M. exigua population

The reaction of seven genotypes of Coffea arabica to 10 Meloidogyne spp. populations collected mainly from coffee plantations in Brazil and Costa Rica was evaluated under greenhouse conditions. The inoculum consisted of 10,000 eggs per plant. Evaluations were done 8 months after inoculations considering the root fresh weight, gall and egg mass indices, number of eggs per gram of root and reproduction factor (RF). The cultivars Obata IAC 1669-20, Sarchimor IAC 4361 and Tupi Amarelo IAC 5111 exhibited susceptibility to the four Brazilian M. exigua populations tested. However, cv. Tupi Vermelho IAC 1669-33 revealed resistance (RF value of 0.7) to the M. exigua population from Lavras, Minas Gerais State, Brazil. A population of M. exigua from Bom Jesus de Itabapoana, Rio de Janeiro State, Brazil, was highly virulent on cv. IAPAR 59 (RF= 165.7), bearing resistance gene Mex-1, and was also virulent on genotype Paraiso (H 419-5-4-5-2) (RF=396.2). A Meloidogyne sp. population on coffee from Garca, Sao Paulo State, Brazil, reproduced at low rates (RF ranging from 0.1 to 3.9) on all genotypes. All tested cultivars were susceptible to M. incognita and M. paranaensis. M. mayaguensis of guava from Parana State, Brazil, reproduced at low rates in all coffee genotypes; however, another population of coffee, from Costa Rica, was more aggressive and showed RF value that ranged from 0.8 to 12.4. Results of this study point for the first time to the ability of a naturally occurring M. exigua population to overcome the resistance conferred by the Mex-1 gene.

Níveis nutricionais de metionina + cistina digestível para poedeiras semipesadas no segundo ciclo de produção

Um experimento foi conduzido com o objetivo de estabelecer a exigência nutricional de metionina + cistina (met + cist) para poedeiras semipesadas no segundo ciclo de produção. Utilizaram-se 180 poedeiras semipesadas no período de 79 a 95 semanas de idade alimentadas com uma ração basal deficiente em met + cist (0,490%) suplementada com 0,00; 0,053; 0,108; 0,161; e 0,214% de DL-metionina (98%), de forma a proporcionar 0,490; 0,542; 0,594; 0,648; e 0,698% de met + cist digestível. Os níveis de suplementação de met + cist obedeceram, respectivamente, às relações de 75, 83, 91, 99 e 107 com lisina. O delineamento experimental foi o inteiramente casualizado com cinco níveis de met + cist, seis repetições e seis aves por unidade experimental. Avaliaram-se os consumos de ração e de met + cist, a conversão alimentar por dúzia e por massa de ovos, o ganho de peso, a taxa de postura, o peso e a massa de ovos, a porcentagem dos componentes dos ovos e a qualidade interna dos ovos. Os níveis de met + cist tiveram efeito linear positivo sobre a conversão alimentar por dúzia de ovos, efeito quadrático sobre o consumo de ração, o ganho de peso e a conversão alimentar. Os níveis de met + cist tiveram efeito linear positivo sobre a taxa de postura e efeito quadrático sobre o peso e a massa de ovos. Observaram-se ainda efeito quadrático sobre a unidade Haugh e efeito linear sobre o índice de gema. A exigência de met + cist é igual ou superior a 0,698%, que corresponde a consumo mínimo de 786 mg de met + cist digestível/ave.dia.

Reação de porta-enxertos comerciais de tomateiro a Meloidogyne mayaguensis

O objetivo do presente trabalho foi verificar a resistência ao nematóide Meloidogyne mayaguensis em oito porta-enxertos de tomateiro considerados resistentes à Meloidogyne incognita, M. javanica e M. arenaria, comercializados no Brasil. Os porta-enxertos testados foram: 'Guardião', 'Helper-M', 'Anchor-T', 'Dr. K', 'Kagemuscha', 'TMA 809', 'Magnet' e 'He-Man'. O experimento constou de 9 tratamentos (8 porta-enxertos e a cultivar Rutgers utilizada como padrão de suscetibilidade), com 6 repetições, sendo cada parcela constituída por 1 planta por vaso, mantidas em casa de vegetação. As plantas foram inoculadas com 5.000 ovos e eventuais juvenis infectantes de M. mayaguensis. O experimento seguiu o delineamento inteiramente casualizado. Aos 60 dias da inoculação procederam-se as avaliações, quando foram avaliados os índices de galhas e massas de ovos, número de nematóides no solo e na raiz, peso do sistema radicular e o fator de reprodução. Todos os porta-enxertos estudados demonstraram-se suscetíveis a M. mayaguensis.

Histology of the interactions of Paecilomyces lilacinus with Meloidogyne incognita on Eclipta alba (L.)

Under greenhouse conditions, the experiment was conducted to test the efficacy of opportunistic and nematophagous hyphomycete, Paecilomyces lilacinus against root-knot nematode, Meloidogyne incognita on Eclipta alba. The treatment comprised inoculation of E. alba with M. incognita alone (N) and in combination with P. lilacinus (one week before (T1), simultaneously (T2), one week after (T3), two weeks after (T4) and three weeks after (T5)). The results showed that the application of P. lilacinus before one week of nematode inoculation (Tl) was more effective than other treatments. A significant enhancement was noticed in the growth and yield of E. alba. Root-knot and egg mass indices were suppressed due to destruction of the mature females and the egg masses. Histopathological studies revealed the presence of P. lilacinus hyphae in and around the females and the eggs.

Inconsistency of the biological control of Meloidogyne incognita race 2 in melon by endophytic bacteria

We obtained 61 rhizobacterium isolates from rhizosphere soil samples collected in melon commercial fields located in Mossoró, Rio Grande do Norte State, Brazil. These isolates, along with 56 endophytic bacteria from the Collection of Cultures of the Plant Bacteriology Laboratory of the Universidade Federal Rural de Pernambuco, were tested for controlling Meloidogyne incognita race 2 in melon. To infest the soil with nematodes, 1000 eggs of Meloidogyne incognita race 2 per plant were placed in pots where seedlings of the yellow-type melon, cultivar AF 682, were growing for 10 days. Two days before, 20 mL of bacterial suspension (0.7 OD570nm) were poured into each pot. After 60 days, fresh root biomass, gall index, egg mass, and the nematode reproduction factor were assessed. Among the 117 isolates screened, the endophytic Bacillus ENM7, ENM10, and ENM51 were selected because they significantly reduced egg mass and/or gall index. However, when tested again, separately and in mixtures, these isolates nor confirmed their efficiency in vivo, neither affected juvenile emergence in vitro. These results give evidence on the inconsistency of using endophytic-bacteria in the control of M. incognita race 2 in melon.